Note that the JUNCTION point "Application Data" points right back to the same folder. Recursing into Application Data takes you right back into ProgramData. This seems to be the source of the problem. Any process trying to traverse this folder and all subfolders will fall into the endless pit of infinite recursion. Thinking that something might have scrambled my Windows installation, I fired up my vmWare copy of Windows 7 and found the same structure in my virtual machine. It appears this is deliberate but, for the life of me, I can't understand why. Can anyone explain this bizarre behaviour?